1. Field of the Invention
The present invention relates generally to an electrochromic device used as a display unit, a dimmer or the like. More particularly, a driver arrangement for the electrochromic device is disclosed.
2. Description of the Related Art
Electrochromic devices (referred to as ECD hereinafter) having an electrochromic elements (referred to as ECE hereinafter) are generally known. A typical ECD of a related art is disclosed in U.S. Pat. No. 4,750,816. The ECE disclosed therein has a pair of transparent electrodes disposed between a pair of transparent bases. Between the electrodes, two facing color-developing layers are provided. One is an organic oxidation color-developing layer made of polyaniline, and the other is an inorganic reduction color-developing layer made of tungsten oxide. An electrolyte layer is formed between the color-developing layers. The ECD also has a voltage stabilizer which applies a predetermined voltage to the ECE during a color-developing process and a reverse voltage during a color-fading process.
In the foregoing ECD however, extended repetitions of the color-developing and fading actions will cause an uneven distribution of electric charge due to properties of the electrolyte. This changes the electric potential of the color-developing layers. Such electrical variation tends to deteriorate the polyaniline layer thereby reducing the ECE's ability to fully fade.